WO2020137681A1 - Composite, and structure and thermistor using same - Google Patents

Abstract

The present invention provides a metal-oxide-containing composite, wherein metal elements in the metal oxide include at least one of Mn and Ni, and the composite is a novel composite having high density and high strength. The present invention provides a composite including a plurality of first particles comprising a metal oxide including at least one first metal element, and a first amorphous phase which is interposed between the plurality of first particles and which includes the same metal element as the first metal element, the first metal element including at least one of Mn and Ni.

Description

Composite and structure and thermistor using the same

The present invention relates to a composite, more specifically, a metal oxide-containing composite, and a structure and a thermistor using the composite.

-Thin film thermistors that use a metal oxide film that exhibits a large negative temperature coefficient as the thermistor layer are widely used as temperature sensors in various devices and devices. Generally, a thin film thermistor is formed by forming a metal electrode on a base material and then contacting a metal oxide film that functions as a thermistor layer with a layer made of a sintered body of metal oxide particles. It is manufactured by forming it.

Such a manufacturing method has a problem that the bonding strength at the interface between the metal oxide film and the metal electrode is small, and in some cases interface peeling may occur. This problem occurs because the metal oxide particles are subjected to heat treatment at 400° C. or higher and sintered to form a metal oxide film exhibiting high thermistor characteristics. It is considered that this occurs because cracks and interfacial peeling occur due to the difference in the coefficient of thermal expansion. In order to achieve both high thermistor characteristics and high bonding strength with respect to this problem, various measures have been conventionally proposed (for example, refer to Patent Documents 1 to 4).

International Publication No. 2014/010591 JP, 2008-244344, A Japanese Unexamined Patent Publication No. 2015-065417 JP, 2013-179161, A U.S. Patent Application Publication No. 2017/0088471

However, the conventional measures have not always been sufficiently satisfactory for manufacturing a thin film thermistor that achieves both desired electrical characteristics (for example, high thermistor characteristics) and high bonding strength.

Solution methods and vapor phase methods are generally known as methods for forming metal oxide films on various types of substrates, but they were carried out at low temperatures where metal and resin substrates were not affected. In this case, the quality of the metal oxide film formed by this is low, and desired electrical characteristics cannot be obtained. Room temperature solidification techniques such as the aerosol deposition method are also known, but they are not suitable for mass production because of the low film formation rate. How to enable low-temperature sintering by adding SiO ₂ glass metal oxide, SiO ₂ becomes a cause of high resistance, causing a decrease in electrical characteristics. There is also a method that enables sputtering at room temperature by using a nitride, but nitride has a problem in stability in the atmosphere, and sputtering has a drawback that the bonding strength is low due to its construction method. is there.

Under such circumstances, in recent years, a low temperature sintering (CS) method has been developed which can sinter metal oxide particles at a low temperature of 200° C. or lower (see Patent Document 5). In this low temperature sintering method, the metal oxide particles are mixed with a solvent (water and an acid or alkali) capable of partially dissolving the oxide and heated and pressed at 200° C. or less to theoretically It is said that a sintered body having a density of 85% or more of the density can be formed. However, this low-temperature sintering method cannot form a high-density sintered body (metal oxide film) with respect to Mn and/or Ni oxide particles, and the strength of the sintered body itself is low. Results in another problem that is not enough.

The present inventor has conducted earnest research to independently combine metal oxide particles with other materials in order to address the above-mentioned conventional problems. One object of the present invention is to provide a novel composite (also referred to herein as "metal oxide-containing composite") composed of a plurality of particles of a metal oxide, which comprises It is to realize a novel composite in which the metal element contains at least one of Mn and Ni, and which itself has high strength. Another object of the present invention is to provide a structure using such a composite, wherein the composite is bonded to a metal part with high bonding strength. Still another object of the present invention is to provide a thermistor using such a structure, which can achieve both desired electrical characteristics and high bonding strength.

According to the first aspect of the present invention,
A plurality of first particles made of a metal oxide containing at least one first metal element;
A composite including a first amorphous phase existing between the plurality of first particles and containing the same metal element as the first metal element, wherein the first metal element contains at least one of Mn and Ni. Will be provided.

In one aspect of the first aspect of the present invention, the first metal element may further include at least one selected from the group consisting of Fe, Al, Co and Cu.

In one aspect of the first aspect of the present invention, the composite may further include a plurality of second particles composed of a first resin, wherein the first amorphous phase includes the plurality of first particles and the plurality of first particles. It may be between the second particles.

In one embodiment of the first aspect of the present invention, the first resin is at least one selected from the group consisting of polyethylene terephthalate, polyetherimide, polyamideimide, polyimide, polytetrafluoroethylene, epoxy resin and liquid crystal polymer. May be included.

In one aspect of the first aspect of the present invention, the thickness of the first amorphous phase may be 100 μm or less.

In one aspect of the first aspect of the present invention, some of the plurality of first particles may be in contact with each other.

According to the second aspect of the present invention,
A plurality of first particles made of a metal oxide containing at least one first metal element;
A plurality of second particles made of a first resin and a first amorphous phase containing the same metal element as the first metal element;
The first particles are in contact with each other, the second particles are present inside the first particles in contact with each other, and the first amorphous phase is in contact with the first particles in contact with each other. There is provided a composite existing between particles and the second particles, wherein the first metal element contains at least one of Mn and Ni.

In one aspect of the second aspect of the present invention, the first metal element may further include at least one selected from the group consisting of Fe, Al, Co and Cu.

In one embodiment of the second aspect of the present invention, the first resin is at least one selected from the group consisting of polyethylene terephthalate, polyetherimide, polyamideimide, polyimide, polytetrafluoroethylene, epoxy resin and liquid crystal polymer. May be included.

In one aspect of the second aspect of the present invention, the thickness of the first amorphous phase may be 100 μm or less.

According to the third aspect of the present invention,
A metal part containing at least one second metal element,
With the complex of the present invention,
A structure including a bonding layer located between the metal part and the composite, wherein the bonding layer includes a second amorphous phase containing the same metal element as the first metal element and the second metal element. Will be provided.

In one aspect of the third aspect of the present invention, the second metal element is selected from the group consisting of Mn, Ni, Fe, Al, Zn, Cr, Ti, Co, Cu, Ag, Au and Pt. It may include at least one.

According to the fourth aspect of the present invention,
A resin base material made of a second resin,
There is provided a thermistor including the structure of the present invention arranged on the resin substrate, wherein the metal part includes two metal electrodes.

In one aspect of the fourth aspect of the present invention, the composite and the bonding layer may have a total thickness of 100 μm or less.

In one aspect of the fourth aspect of the present invention, the second resin is at least one selected from the group consisting of polyethylene terephthalate, polyetherimide, polyamideimide, polyimide, polytetrafluoroethylene, epoxy resin and liquid crystal polymer. May be included.

In one aspect of the fourth aspect of the present invention, the two metal electrodes have main surfaces facing each other, and the composite can be interposed between the main surfaces.

In one aspect of the fourth aspect of the present invention, the two metal electrodes can be electrically connected to two external electrodes that are alternately arranged in a plan view.

According to the present invention, a novel metal oxide-containing composite, in which the metal element in the metal oxide contains at least one of Mn and Ni, and which itself has high density and high strength is realized. To be done. Furthermore, according to the present invention, a composite having a small change in resistivity before and after being left in a high temperature and high humidity environment is realized. Further, according to the present invention, there is provided a structure using such a composite, wherein the composite is bonded to a metal part with high bonding strength. Further, according to the present invention, there is provided a thermistor using such a structure, which can achieve both desired electrical characteristics and high bonding strength.

FIG. 1 is a partial schematic view showing the structure of a composite according to one embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing one example of the structure in one embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing another example of the structure according to the embodiment of the present invention. FIG. 4 is a diagram showing an example of a thermistor in one embodiment of the present invention, FIG. 4A is a schematic cross-sectional view taken along line XX in FIG. 4B, and FIG. Is a schematic top view. FIG. 5 is a diagram showing another example of the thermistor in one embodiment of the present invention, FIG. 5A is a schematic cross-sectional view taken along line XX in FIG. ) Is a schematic top view. FIG. 6 is a diagram showing another example of the thermistor in one embodiment of the present invention, FIG. 6A is a schematic cross-sectional view taken along line XX in FIG. 8A is a schematic top view showing the resin base material located on the upper side in FIG. FIG. 7 is a diagram showing another example of the thermistor in one embodiment of the present invention, in which (a) is a schematic cross-sectional view seen from line XX in (b), 8A is a schematic top view showing the resin base material located on the upper side in FIG. FIG. 8 is a diagram showing another example of the thermistor in one embodiment of the present invention, FIG. 8A is a schematic cross-sectional view taken along line XX in FIG. 8B, ) Is a schematic top view. FIG. 9 is a diagram showing another example of the thermistor in one embodiment of the present invention, FIG. 9A is a schematic cross-sectional view taken along line XX in FIG. ) Is a schematic top view. FIG. 10(a) is a partial schematic diagram showing the structure of the complex according to another embodiment of the present invention, and FIG. 10(b) shows a modified example of the complex of FIG. 10(a). FIG. 11: is a schematic cross section which shows one example of the structure in another embodiment of this invention. FIG. 12 is a schematic cross-sectional view showing another example of the structure according to another embodiment of the present invention. FIG. 13 is a scanning transmission electron microscope (STEM) observation image (bright-field image) of a partially enlarged cross section of the structure manufactured in Example 1 of the present invention, and (a) is a metal oxide-containing composite. 13B is a STEM observation image of a cross section of the junction between the layer and the lower electrode and the vicinity thereof, (b) shows the element distribution of C (carbon) in FIG. 13( a ), and (c) shows Mn of (a). The element distribution of (manganese) is shown, and (d) shows the element distribution of Cu (copper) of (a). FIG. 14 is a scanning transmission electron microscope (STEM) observation image (bright-field image) of a partially enlarged cross section of the structure manufactured in Example 3 of the present invention, and (a) is a metal oxide-containing composite. 13B is a STEM observation image of a cross section of the junction between the layer and the lower electrode and the vicinity thereof, (b) shows the element distribution of C (carbon) in FIG. 13( a ), and (c) shows Mn of (a). The element distribution of (manganese) is shown, and (d) shows the element distribution of Cu (copper) of (a). FIG. 15 is a transmission electron microscope (TEM) observation image of a partially enlarged cross section of the structure manufactured in Example 1 of the present invention, and (a) is a TEM observation of the cross section of the metal oxide-containing composite layer. 15B is an enlarged image of the rectangular frame area shown in FIG. 15A, FIG. 15C is an enlarged image of the rectangular frame area shown in FIG. 15B, and FIG. ) Is an example of an electron diffraction image of an amorphous phase shown for the purpose of distinguishing the amorphous phase by distinguishing it from particles having a crystal structure.

A composite according to two embodiments of the present invention, and a structure and a thermistor using the composite will be described below with reference to the drawings. In the drawings, the same members are denoted by the same reference numerals, and the same description applies unless otherwise specified.

(Embodiment 1)
As shown in FIG. 1, the composite body (metal oxide-containing composite body) 10 in the present embodiment is
A plurality of first particles (hereinafter also simply referred to as “metal oxide particles”) 1 made of a metal oxide containing at least one first metal element;
The first amorphous phase 2 existing between the plurality of first particles 1 is included.

The metal oxide forming the metal oxide particles 1 contains at least one of Mn and Ni as the first metal element, and further contains at least one selected from the group consisting of Fe, Al, Co and Cu. You can stay. Mn and/or Ni are essential metal elements in the metal oxide. Further, at least one selected from the group consisting of Fe, Al, Co and Cu is an optional addition metal element in the metal oxide. The optional addition metal element is preferably at least one selected from the group consisting of Fe, Al and Co. Any of these metal oxides may be a metal oxide semiconductor, and may have a spinel structure in particular, but is not limited thereto.

The ratio of the metal element in the entire metal oxide forming the plurality of metal oxide particles 1 is not particularly limited, and can be appropriately selected according to desired electrical characteristics and the like. With respect to the essential metal element, if both Mn and Ni are present, the Mn:Ni ratio (atomic ratio) can be, for example, 1 to 100:1. When the optional addition metal element is present, the optional addition metal element (the total of them when there are a plurality of them) may be smaller than the essential metal element (the total of them when both Mn and Ni are present), but is essential. The ratio (atomic ratio) of metallic element: arbitrarily added metallic element may be, for example, 1 to 100:1.

The average particle size of the metal oxide particles 1 can be, for example, 0.01 μm or more and 100 μm or less, and particularly can be 0.02 μm or more and 1 μm or less. Since the average particle size of the metal oxide particles 1 is in the range of 0.01 μm or more and 100 μm or less, in the production method described later in this embodiment, a liquid medium and/or a fluid (preferably, a fluid) derived from metal acetylacetonate is used. The solvent) makes it easier for the metal oxide particles to be carried into the gaps between the other metal oxide particles, so that the resultant composite can be more effectively densified. In the present specification, the average particle size is a particle size (D50) at a point where the cumulative value is 50% in a cumulative curve in which the particle size distribution is obtained on a volume basis and the total volume is 100%. The average particle diameter can be measured using a laser diffraction/scattering particle diameter/particle size distribution measuring device or an electron scanning microscope.

The metal oxide particles 1 may be a mixture of two or more kinds of metal oxide particles having different metal oxide compositions and/or average particle sizes.

The first amorphous phase 2 exists between the metal oxide particles 1 and can bond the metal oxide particles 1 to each other. Therefore, the composite body 10 of this embodiment itself has high strength. Although not limited to this embodiment, a structure in which a plurality of metal oxide particles 1 are dispersed in a continuous phase of the first amorphous phase 2 can be formed. Further, the composite body 10 of the present embodiment can contain the metal oxide particles 1 at a high density due to the first amorphous phase 2 (a conductive path can be formed by the metal oxide particles 1 dispersed at a high density. it can). Furthermore, the first amorphous phase 2 can exhibit electrical characteristics close to those of the metal oxide (semiconductor) particles 1 having a crystal structure. As a result, it is possible to obtain the same electrical characteristics as a sintered body obtained by sintering metal oxide particles at a high temperature by a conventional method.

The first amorphous phase 2 contains the same metal element as the first metal element contained in the metal oxide particles 1. Thereby, even if mutual diffusion between the metal oxide particles 1 and the first amorphous phase 2 occurs, it is possible to effectively prevent deterioration of the electrical characteristics of the composite body 10.

In the present specification, the amorphous phase means a phase having substantially no crystallinity or a relatively low crystallinity, which is a crystal based on an electron diffraction image which is a method known to those skilled in the art. It can be distinguished from particles having a structure. Further, the elements (particularly metal elements) contained in the amorphous phase can be confirmed by using a scanning transmission electron microscope (STEM).

In the present embodiment, the presence of the first amorphous phase 2 between the metal oxide particles 1 may mean that the space between the plurality of metal oxide particles 1 is filled with the first amorphous phase 2. As a result, pores that may be contained in the composite 10 can be eliminated by filling the first amorphous phase 2, so that the resistance value before and after being left in a high temperature and high humidity environment that is considered to be due to pores. The change can be reduced. When paying attention to any two metal oxide particles 1 adjacent to each other among all the metal oxide particles 1, these two metal oxide particles 1 have a first amorphous phase 2 between them. However, the first amorphous phase 2 may be in contact (preferably bonded) with each other substantially without being present between them. In the former case, the first amorphous phase 2 may be present with a thickness of 100 μm or less. The thickness of the first amorphous phase 2 is preferably small from the viewpoint of electrical characteristics and/or strength. In the latter case described above, a portion where the first amorphous phase 2 is substantially absent may be present in the composite 10.

It should be noted that the composite body 10 (in particular, the first amorphous phase 2) of the present embodiment does not substantially contain silicon oxide such as SiO ₂ glass. Silicon oxide is not preferable because it causes a remarkable deterioration in electrical characteristics. The content of silicon oxide in the composite 10 (based on the total weight of the metal oxide particles) is, for example, 0.1% by mass or less, preferably 0.01% by mass or less, and substantially zero. More preferably, it is mass %.

The composite body 10 of the present embodiment can be arranged (in particular, formed into a film) on an arbitrary object to form a structure. Although not limiting to this embodiment, the composite 10 may be at least partially joined to a metal portion (eg, a member or region made of metal).

For example, as shown in FIG. 2, the structure 20 in one example of the present embodiment is
A metal part 13 containing at least one second metal element,
The composite body 10 of the present embodiment,
The bonding layer 15 is located between the metal part 13 and the composite body 10. In practice, the boundary between the composite body 10 and the bonding layer 15 does not necessarily have to be clear (in the accompanying drawings, a virtual boundary is indicated by a dotted line). In the structure 20, the composite 10 and the bonding layer 15 can be collectively understood as a metal oxide-containing composite layer or a thermistor layer.

The bonding layer 15 includes the second amorphous phase 12. The second amorphous phase 12 can adhere the composite 10 to the metal part 13. Therefore, the structure 20 of the present embodiment can bond the composite 10 to the metal portion 13 with high bonding strength.

Further, in the composite body 10 of the present embodiment, the second amorphous phase 12 contains the same metal element as the first metal element and the second metal element. The second amorphous phase 12 can exhibit electrical characteristics similar to those of the metal oxide (semiconductor) particles 1 having a crystal structure. Furthermore, since the second amorphous phase 12 contains the same metal element as the first metal element and the second metal element, the electrical resistance between the composite body 10, the bonding layer 15, and the metal portion 13 (generally, the metal Schottky barrier between the oxide (semiconductor) particles 1 and the metal part 13, more specifically, between the metal oxide particles 1 and the second amorphous phase 12, and between the second amorphous phase 12 and the metal part 13. It is possible to reduce the interfacial resistance between them and improve the electrical characteristics of the structure 20.

Although not limiting the present embodiment, the second amorphous phase 12 and the first amorphous phase 2 exist continuously (for example, in the intermediate region, forming a gradation and/or intermingling with each other). You can In that case, for example, these boundaries may be determined based on the distribution of the first metal element and the second metal element that may be present in the amorphous phase.

The second metal element forming the metal part 13 is not particularly limited, but is at least one selected from the group consisting of Mn, Ni, Fe, Al, Zn, Cr, Ti, Co, Cu, Ag, Au and Pt. And any one or two or more of these alloys, preferably any one or two or more alloys of Ni, Cu and Ag. The second metal element may be a metal commonly used as an electrode. And/or, the second metal element may be the same or different metal element as the first metal element.

Further, for example, as shown in FIG. 3, in the structure 21 in another example of the present embodiment, the composite body 10 of the present embodiment is bonded to the metal portions 13a and 13b with the bonding layers 15a and 15b, respectively. May be joined via. In the structure 21, the composite 10 and the bonding layers 15a and 15b can be collectively understood as a metal oxide-containing composite layer or a thermistor layer.

The structure 21 has the same effect as that described above for the structure 20. Furthermore, in the structure 21, the metal parts 13 and 13b can be used as counter electrodes, and in this case, the total thickness of the composite 10 and the bonding layers 15a and 15b (thickness of the metal oxide-containing composite layer) is controlled. By doing so, the electrical characteristics of the structure 21 (for example, variations in resistance value) can be effectively controlled.

The structures 20 and 21 of the present embodiment can be appropriately modified and arranged on any base material to form a thermistor. Although not limiting the present embodiment, the structures 20 and 21 may be appropriately modified and arranged on the resin base material (or resin film).

For example, as shown in FIGS. 4A and 4B, the thermistor 30 in one example of the present embodiment is
A resin base material 27 made of a second resin,
A structure 20a of the present embodiment arranged on the resin substrate 27;
including. In the structure 20 a, the metal portion 13 includes two metal electrodes 13 c and 13 d, and the bonding layers 15 c and 15 d are located between them and the composite body 10, respectively. In the thermistor 30, the metal electrodes 13c and 13d of the structure 20a are arranged closer to the resin base material 27 than the composite body 10, but the present embodiment is not limited to this. The exposed portions of the composite body 10 and the bonding layers 15c and 15d may be appropriately protected by a protective film (not shown) made of resin or the like.

The composite body 10 and the bonding layers 15c and 15d interposed between the metal electrodes 13c and 13d can function as a thermistor layer whose resistance can change depending on temperature (more specifically, has a negative temperature coefficient). .. In FIG. 4B, the metal electrodes 13c and 13d located below the composite body 10 are shown in a perspective view.

In the thermistor 30 of the present embodiment, the composite 10 can contain the metal oxide particles 1 at a high density due to the first amorphous phase 2, and the first amorphous phase 2 and the second amorphous phase 12 are metal oxides. Since the (semiconductor) particles 1 can exhibit electrical characteristics close to those of the (semiconductor) particles 1, the same electrical characteristics as a sintered body obtained by sintering metal oxide particles at a high temperature by a conventional general method can be obtained, and desired electrical characteristics ( For example, thermistor characteristics, more specifically room temperature resistivity, B constant, etc.) can be achieved. In addition, in the thermistor 30 of the present embodiment, the composite body 10 can be firmly bonded to the metal electrodes 13c and 13d via the bonding layers 15c and 15d, and high bonding strength can be achieved. In addition, due to the high bonding strength, variations in the resistance value of the thermistor 30 are small, and high reliability can be achieved.

In the thermistor 30, the total thickness of the composite 10 and the bonding layers 15c and 15d formed on the resin base material 27 (thickness of the metal oxide-containing composite layer that can function as a thermistor layer) is, for example, 100 μm or less. And more specifically 1 μm or more and 30 μm or less. The thermistor 30 is also called a thin film thermistor.

Since the thermistor 30 is thin as described above, it can be easily installed in a small space. Furthermore, it is possible to reduce physical damage due to pressurization during attachment and operation to both the thermistor 30 and the object to which it is attached. Furthermore, since the thermistor 30 has a small heat capacity, it exhibits high temperature responsiveness. Further, since the composite body 10 (and the bonding layers 15c and 15d) is thin and has flexibility, it is difficult to be destroyed even if it is deformed. In particular, when a flexible substrate (or film) is used as the resin substrate 27, the thermistor 30 that is flexible as a whole can be obtained.

The second resin constituting the resin base material 27 is not particularly limited, but is, for example, a group consisting of polyethylene terephthalate, polyetherimide, polyamideimide, polyimide, polytetrafluoroethylene, epoxy resin and liquid crystal polymer (LCP: Liquid Crystal Polymer). It may include at least one more selected. Among them, polyimide and polyamide-imide are preferable from the viewpoint of heat resistance and adhesiveness.

The thickness of the resin base material 27 is not particularly limited, but in the case of a thin film thermistor, it may be, for example, 1 to 50 μm.

The thermistor 30 of this embodiment can be modified in various ways. For example, as shown in FIGS. 5A and 5B, the thermistor 31 is
A resin base material 27 made of a second resin,
A structure 20b of the present embodiment arranged on the resin base material 27;
including. In the structure 20b, the metal part 13 includes two metal electrodes 13e and 13f, and the bonding layers 15e and 15f are located between the metal electrodes 13e and 13f and the composite 10, respectively. In the thermistor 31, the composite body 10 of the structure 20b is arranged closer to the resin base material 27 than the metal electrodes 13e and 13f. The exposed portions of the composite body 10 and the bonding layers 15e and 15f may be appropriately protected by a protective film (not shown) made of resin or the like.

Further, for example, as shown in FIGS. 6A and 6B, the thermistor 32 has main surfaces where two metal electrodes 13g and 13i face each other, and the composite body 10 is interposed between the main surfaces. , The bonding layers 15g and 15i may be bonded to each other, and the two metal electrodes 13h and 13i have main surfaces facing each other, and the composite body 10 is interposed between the main surfaces. , 15i. In other words, the thermistor 32 has a structure in which two elements are connected in series. In the structure 20c, the metal portion 13 includes three metal electrodes 13g, 13h, and 13i, and the bonding layers 15g, 15h, and 15i are located between them and the composite body 10, respectively. In FIG. 6B, the resin base material 27b is excluded, and the metal electrodes 13g and 13h are shown in a perspective view. According to this configuration, the total thickness of the composite 10 and the bonding layers 15g and 15i (corresponding to the thickness of the metal oxide-containing composite layer, that is, the thermistor layer, indicated by a symbol "t" in the drawing) is calculated. By controlling, the electric characteristics of the thermistor 32 can be controlled (for example, the variation in resistance value can be further reduced), and higher temperature resolution can be achieved. In the illustrated embodiment, the metal electrodes 13g and 13h are electrically connected to (and/or integrally formed with, the external electrodes 14a and 14b, the same applies hereinafter), but the invention is not limited thereto. Further, in the illustrated embodiment, the thermistor 32 includes the resin base materials 27a and 27b, but only one of them may be provided.

Further, for example, as shown in FIGS. 7A and 7B, in the thermistor 33, the two metal electrodes 13g and 13h′ are respectively arranged with two external electrodes 14a and 14b′ which are alternately arranged in a plan view. It may be electrically connected. In the structure 20d, the metal part 13 includes three metal electrodes 13g, 13h′, 13i, and the bonding layers 15g, 15h′, 15i are respectively located between them and the composite 10 (others are described above. Of thermistor 32). With this configuration, even when the thermistor 33 is extremely small and difficult to handle, the thermistor 33 can be mounted relatively easily.

Further, for example, as shown in FIGS. 8A and 8B, the thermistor 34 has two metal electrodes 13j and 13l having main surfaces facing each other, and the composite body 10 is interposed between the main surfaces. , The two metal electrodes 13k and 13l have main surfaces facing each other, and the composite body 10 is interposed between the main surfaces, and the bonding layers 15k and 15l are bonded to each other. , 15 l. In other words, the thermistor 34 has a structure in which two elements are connected in series. In the structure 20e, the metal portion 13 includes three metal electrodes 13j, 13k, and 13l, and the bonding layers 15j, 15k, and 15l are located between them and the composite body 10, respectively. Further, in the thermistor 34, the two metal electrodes 13j and 13k may be electrically connected to the two external electrodes 14c and 14d, which are alternately arranged in a plan view. With such a configuration, by controlling the thickness of the metal oxide-containing composite layer, the electrical characteristics of the thermistor 34 can be controlled, and higher temperature resolution can be achieved. Moreover, according to this structure, the thermistor 34 can be mounted relatively easily.

Further, for example, as shown in FIGS. 9A and 9B, in the thermistor 35, the metal electrodes 13m and 13n formed on the same plane may be formed to face each other in a comb shape. In the structure 20f, the metal portion 13 includes two metal electrodes 13m and 13n, and the bonding layers 15m and 15n are located between them and the composite body 10, respectively. As a result, the electrical characteristics of the thermistor 35 can be controlled (for example, the variation in resistance value can be further reduced), and high temperature resolution can be achieved. Also in the thermistor 35, the two metal electrodes 13m and 13n may be electrically connected to the two external electrodes 14c' and 14d' which are alternately arranged in a plan view. With this configuration, the thermistor 35 can be mounted relatively easily.

Further, for example, the composite layer and the bonding layer may be embedded in a part of the resin base material or the metal part exposed in the specific structure of the thermistor (see, for example, FIG. 9 ).

The composite body, structure body and thermistor of the present embodiment described above can be manufactured by any appropriate method, for example, the following method. Hereinafter, as a method of manufacturing the thermistor, the above-described method of manufacturing the thermistor 30 will be exemplarily described with reference to FIGS. 1, 2, and 4. However, other thermistors can be understood by appropriately combining known techniques, Each manufacturing method of the composite and the structure can be understood by referring to only the corresponding portion.

First, the metal electrodes 13c and 13d are formed as the metal portion 13 on the resin base material 27. The metal electrodes 13c and 13d can be patterned by any appropriate method such as photolithography, plating, vapor deposition, and sputtering.

Next, a predetermined region of the resin base material 27 on which the metal electrodes 13c and 13d are formed as the metal parts 13 as described above (the composite 10 and the bonding layers 15c and 15d, in other words, the metal oxide-containing composite layer is formed). A mixture containing the metal oxide particles 1 and the metal acetylacetonate (hereinafter, also referred to as “raw material mixture” in the present specification) is applied to a region to be formed), and the mixture of the metal acetylacetonate is added under pressure. By heating at a temperature equal to or higher than the melting point and equal to or lower than 600° C., the composite body 10 and the bonding layers 15c and 15d are simultaneously and integrally formed in the form of a sintered body containing the metal oxide particles 1.

The raw material mixture can be applied (eg, applied, printed (screen printed, etc.)) to a predetermined area by a method known to those skilled in the art, for example, coating, dipping, laminating, spraying or the like. The base material to which the raw material mixture is applied is subjected to a treatment such as drying under heating or natural drying, if necessary, and then, under a pressure using a means known to those skilled in the art such as a press. It can be heated at a temperature above the melting point of metal acetylacetonate and below 600°C.

In the present specification, a metal acetylacetonate is a metal acetylacetonate salt, and more specifically, a bidentate acetylacetonate ion ((CH ₃ COCHCOCH ₃ ) ⁻ , hereinafter referred to by an abbreviation ( acac) ^-, which may be referred to as "), and a central metal. The metal element contained in the metal acetylacetonate is preferably any one or two or more elements selected from the above-mentioned first metal elements, and is the same as the first metal element contained in the metal oxide particles 1. More preferably, it is a metal element, but not limited to this.

As the metal acetylacetonate, one kind of metal acetylacetonate may be used, or two or more kinds of metal acetylacetonate may be used in combination. When two or more first metal elements contained in the metal oxide particles 1 exist, two or more kinds of metal acetylacetonates may be used in combination according to the abundance ratio of these metal elements. Not limited to.

A raw material mixture is obtained by mixing the metal oxide particles and the metal acetylacetonate. The mixing of the metal oxide particles and the metal acetylacetonate can be performed in an atmosphere of normal temperature and normal humidity and atmospheric pressure. The metal acetylacetonate may be mixed in a ratio of, for example, 0.1% by mass or more and 50% by mass or less, preferably 1% by mass or more and 30% by mass or less, based on the total mass of the metal oxide particles. And more preferably 2% by mass or more and 10% by mass or less.

The metal acetylacetonate to be mixed may be in any state. For example, the raw material mixture may be obtained by mixing the metal oxide particles and the dry powdery solid metal acetylacetonate. In this case, the metal oxide particles and the powdery metal acetylacetonate are, for example, one or more kinds selected from the group consisting of water, acetylacetone, alcohols containing methanol and/or ethanol, etc. under atmospheric pressure. The raw material mixture is obtained by mixing using a general mixing method which is carried out in the solvent of 1 or in one or more kinds of gas selected from the group consisting of air, nitrogen and the like.

Alternatively, the raw material mixture may be obtained by mixing the metal oxide particles, the metal acetylacetonate, and the solvent. Any appropriate solvent may be used as the solvent, and may be, for example, one or a mixture of two or more selected from the group consisting of water, acetylacetone, alcohols including methanol and/or ethanol, and the like. The solvent is not particularly limited as long as it is suitable for heating the raw material mixture under pressure, and is not particularly limited, but is, for example, 50 mass% or less, preferably 30 mass% with respect to the total mass of the metal oxide particles. % Can be mixed. Upon mixing, the metal acetylacetonate and the solvent may be used separately, or a liquid material in which the metal acetylacetonate is dispersed or dissolved in the solvent may be used. In the latter case, the liquid obtained by synthesizing the metal acetylacetonate may be used without separating the metal acetylacetonate. More specifically, metal acetylacetonate can be synthesized by mixing liquid acetylacetone and a metal compound (for example, metal hydroxide or chloride), and the liquid product after synthesis can be used as it is or as needed. A solvent can be added accordingly and used.

The raw material mixture may further contain, in addition to the metal oxide particles and the metal acetylacetonate, any appropriate material in an amount that does not adversely affect desired electrical characteristics. More specifically, the raw material mixture may further contain additives such as a pH adjuster, a sintering aid, and a pressure relief agent. These additives may be mixed in a proportion of, for example, 0.01% by mass or more and 10% by mass or less, preferably 0.01% by mass or more and 1% by mass or less, based on the total mass of the metal oxide particles. They are mixed, and more preferably in a proportion of 0.01% by mass or more and 0.1% by mass or less.

By heating the raw material mixture obtained as described above under pressure at a temperature not lower than the melting point of metal acetylacetonate and not higher than 600° C., a relatively high density sintered body can be formed. .. In this heating step, the metal acetylacetonate liquefies and can function as a liquid medium. The heating is preferably performed in the presence of fluid. In the present specification, the fluid is, for example, a liquid, preferably a liquid that can be used as a solvent, and more preferably water. For example, when water is present when the raw material mixture is heated and pressurized, water is present at the interface of the metal oxide particles contained in the raw material mixture. Thereby, the raw material mixture can be sintered at a lower temperature, and the strength of the sintered body can be effectively improved.

In the present specification, the state in which the mixture is in the presence of water means that water may not be positively added to the mixture, and only a slight amount of water is present at the interface of the metal oxide particles. The metal oxide particles may absorb moisture at room temperature. The positive addition of water may be performed by including (mixing) the raw material mixture, or may be performed by heating and pressurizing the raw material mixture in a steam atmosphere. In particular, when water is present by being mixed with the raw material mixture, the water can be effectively spread to the interface of each particle. When water is mixed in the raw material mixture, its amount is not particularly limited, but may be, for example, 20% by mass or less, preferably 15% by mass or less, based on the total mass of the metal oxide particles. Specifically, it is 10% by mass. When the water content in the raw material mixture is 20% by mass or less, water can be mixed in the raw material mixture, and deterioration of the moldability of the raw material mixture can be prevented more effectively. In order to effectively achieve the improvement of the strength of the sintered body, it is preferable to use as much water as possible within the above range, specifically 10% by mass or more and 20% by mass or less of water. Further, in order to carry out molding more easily, it is preferable to use as little water as possible within the above range, specifically, more than 0% by mass and 10% by mass or less of water.

The pressure applied to the raw material mixture may be, for example, 1 MPa or more and 5000 MPa or less, preferably 5 MPa or more and 1000 MPa or less, and more preferably 10 MPa or more and 500 MPa or less. In the present specification, pressing of the raw material mixture means pressing force (or physical/mechanical force) to the raw material mixture (more specifically, a solid component contained in the raw material mixture), for example, by using a pressure molding machine. Pressure) is meant. Therefore, it should be noted that even when the raw material mixture is under pressure, the liquid component contained in the raw material mixture is exposed to the pressure of the ambient atmosphere (usually atmospheric pressure).

The heating temperature of the raw material mixture (hereinafter, also referred to as “heating temperature” in the present specification) refers to the firing temperature, and may be the temperature of the melting point of the metal acetylacetonate contained in the raw material mixture or more and 600° C. or less. .. In the present specification, the melting point refers to a temperature measured by a measuring method defined by JIS standard at room temperature and atmospheric pressure. Each melting point changes depending on various conditions such as pressure at the time of pressurization. The melting points of various metal acetylacetonates are shown in Table 1 below. When two or more kinds of metal acetylacetonates are used, the “melting point of metal acetylacetonate” means the highest melting point of all the metal acetylacetonates. The heating temperature of the raw material mixture depends on the kind of the metal oxide used and the like, but may be higher than the melting point of the metal acetylacetonate by 5°C or higher and 600°C or lower, for example, 100°C or higher and 600°C or lower. Yes, it is preferably 100°C or higher and 400°C or lower, and more preferably 100°C or higher and 300°C or lower.

By thus heating the raw material mixture under pressure at a temperature equal to or higher than the melting point of the metal acetylacetonate, a relatively high density sintered body can be formed at the low temperature as described above. In the present specification, the term “relatively high density” means that the ratio of the density to the theoretical density of the sintered body thus obtained is such that the metal oxide particles contained in the raw material mixture alone (the metal acetylacetonate is allowed to exist). It means that it is higher than the ratio of the density to the theoretical density of the sintered body obtained when heated and pressed under the same temperature and pressure conditions. The sintered body obtained according to the present embodiment may have a relatively high density, and the ratio of the density to the theoretical density depends on the composition of the metal oxide particles used and the like, but is, for example, 70% or more, preferably 80. % Or more. The metal oxide contained in the obtained sintered body may be considered to be substantially the same as the metal oxide of the metal oxide particles contained in the raw material mixture. The time for heating and pressurizing the raw material mixture can be appropriately selected, but is preferably 1 second or more and 120 minutes or less.

As described above, the sintered body formed by using the raw material mixture containing the metal oxide particles and the metal acetylacetonate in contact with the metal part 13 (the metal electrodes 13c and 13d in FIG. 4) is As schematically shown in FIGS. 1 and 2, the composite 10 including the metal oxide particles 1 and the first amorphous phase 2 and the bonding layer 15 including the second amorphous phase 12 (bonding layers 15c and 15d in FIG. 4). ) Corresponds to. The first amorphous phase 2 contains a metal element derived from metal acetylacetonate (the same metal element as the first metal element). The second metal element of the metal part 13 ( metal electrodes 13c and 13d in FIG. 4) can move to the second amorphous phase 12 by thermal diffusion. Therefore, in the second amorphous phase 12, in addition to the metal element derived from the metal acetylacetonate (the same metal element as the first metal element), the metal element derived from the metal part 13 (the same metal element as the second metal element) is also included. Will be included.

As a result, the thermistor 30 exemplified in this embodiment is manufactured. The exposed portions of the composite body 10 and the bonding layers 15c and 15d may be appropriately protected by a protective film (not shown) made of resin or the like.

(Embodiment 2)
The present embodiment is a modification of the composite body, structure, and thermistor described in the first embodiment, and the same explanations as in the first embodiment apply unless otherwise specified.

As shown in FIG. 10A, the composite body 11 according to the present embodiment is
A plurality of first particles (that is, the above-mentioned “metal oxide particles”) 1 made of a metal oxide containing at least one first metal element;
A first amorphous phase 2 containing the same metal element as the first metal element,
A plurality of second particles (hereinafter, also simply referred to as “resin particles” in the present specification) 3 made of a first resin, and the first amorphous phase 2 includes a plurality of metal oxide particles 1 and a plurality of resin particles. It exists between three.

The first resin forming the resin particles 3 is preferably a resin that is not easily melted by heat, and examples thereof include polyethylene terephthalate, polyetherimide, polyamideimide, polyimide, polytetrafluoroethylene, epoxy resin and liquid crystal polymer (LCP). : Liquid Crystal Polymer).

The average particle size of the resin particles 3 may be, for example, 0.001 μm or more and 100 μm or less, and particularly 0.001 μm or more and 1 μm or less. Within this range, the effect of deterioration of characteristics due to addition of resin is small.

The resin particles 3 may be a resin material and/or a mixture of two or more kinds of resin particles having different average particle diameters.

In the present embodiment, the first amorphous phase 2 exists between the metal oxide particles 1 and the resin particles 3 (more specifically, between any particles selected from the metal oxide particles 1 and the resin particles 3). The metal oxide particles 1 and the resin particles 3 can be adhered to each other. Further, in the composite body 11 of the present embodiment, the resin particles 3 are mixed in the metal oxide particles 1, so that the bonding strength between the particles can be improved. Therefore, the composite body 11 of the present embodiment itself has higher strength. The composite 11 of the present embodiment can contain the metal oxide particles 1 at a relatively high density due to the first amorphous phase 2 even if the resin particles 3 are present (the resin particles 3 are present. Also, a conductive path can be formed by the metal oxide particles 1 dispersed at a high density). Furthermore, the first amorphous phase 2 can exhibit electrical characteristics close to those of the metal oxide (semiconductor) particles 1 having a crystal structure. As a result, it is possible to obtain the same electrical characteristics as a sintered body obtained by sintering metal oxide particles at a high temperature by a conventional method.

In the present embodiment, the presence of the first amorphous phase 2 between the metal oxide particles 1 and the resin particles 3 means that the space between the plurality of metal oxide particles 1 and the plurality of resin particles 3 is the first amorphous phase 2. It can mean filling. As a result, the pores that may be contained in the composite 10 can be replaced with the plurality of resin particles 3 and can be eliminated by filling the first amorphous phase 2, so that the high temperature and high humidity considered to be caused by the pores. It is possible to further reduce the change in resistance value before and after being left in the environment. When paying attention to any two metal oxide particles 1 adjacent to each other among all the metal oxide particles 1, these two metal oxide particles 1 have a first amorphous phase 2 between them. However, the first amorphous phase 2 may be in contact (preferably bonded) with each other substantially without being present between them. In the former case, the first amorphous phase 2 may be present with a thickness of 100 μm or less. The thickness of the first amorphous phase 2 is preferably small from the viewpoint of electrical characteristics and/or strength. In the latter case described above, a portion where the first amorphous phase 2 is substantially absent may be present in the composite 11.

It is preferable that the complex 11 of the present embodiment is modified as a complex 11′ shown in FIG. The composite body 11′ shown in FIG.
A plurality of first particles (that is, the above-mentioned “metal oxide particles”) 1 made of a metal oxide containing at least one first metal element;
A first amorphous phase 2 containing the same metal element as the first metal element,
A plurality of second particles (hereinafter, also simply referred to as “resin particles” in the present specification) 3 made of the first resin, the plurality of metal oxide particles are in contact with each other, and the resin particles 3 are in contact with each other. The first amorphous phase 2 exists inside the plurality of metal oxide particles 1 and exists between the plurality of metal oxide particles 1 and the resin particles that are in contact with each other. In the modified composite body 11 ′, the first amorphous phase 2 is substantially absent between the metal oxide particles 1, and all of the plurality of metal oxide particles 1 are in contact (preferably bonded, more preferably, It forms one lump as a whole), and is considered to be an ideal structure in which superior electrical properties and/or higher strength can be expected.
Hereinafter, the description regarding the composite body 11 is similarly applied to the composite body 11 ′ of the modified example.

The content of the resin particles 3 in the composite 11 (relative to the total mass of the composite) may be, for example, 50% by mass or less, and more specifically 5% by mass or more and 20% by mass or less. Within such a range, high strength is realized, but the influence of deterioration of characteristics due to addition of resin is small.

The composite body 11 of the present embodiment can also be arranged (in particular, formed into a film) on an arbitrary object to form a structure. Although not limiting the present embodiment, the composite 11 may be at least partially joined to a metal part (for example, a member or a region formed of a metal).

For example, as shown in FIG. 11, the structure 22 in one example of the present embodiment is
A metal part 13 containing at least one second metal element,
The complex 11 of the present embodiment,
The bonding layer 16 is located between the metal part 13 and the composite body 11. The bonding layer 16 includes the second amorphous phase 12 containing the same metal element as the first metal element and the second metal element.

Further, for example, as shown in FIG. 12, in the structure 23 in another example of the present embodiment, the composite body 11 of the present embodiment is bonded to the metal portions 13a and 13b with the bonding layers 16a and 16b, respectively. May be joined via. The bonding layers 16a and 16 include second amorphous phases 12a and 12b containing the same metal element as the first metal element and the second metal element, respectively.

The structures 22 and 23 of the present embodiment can be similar to the structures described in the first embodiment, except that the resin particles 3 are present in addition to the metal oxide particles 1.

The structures 22 and 23 of the present embodiment can also be appropriately modified and arranged on any base material to form a thermistor. Although not limiting the present embodiment, the structures 22 and 23 may be appropriately modified and arranged on the resin substrate. The thermistor of the present embodiment can also be the same as the thermistor described in the first embodiment except that the resin particles 3 are present in addition to the metal oxide particles 1.

The composite body, structure body, and thermistor of the present embodiment described above can be manufactured by any appropriate method. For example, as a raw material mixture, a mixture containing metal oxide particles 1, resin particles 3, and metal acetylacetonate. It can be manufactured in the same manner as the manufacturing method described in the first embodiment except that the above method is used.

Although the composite according to the two embodiments of the present invention, and the structure and the thermistor using the composite have been described above, the present invention is not limited to these embodiments.

(Example 1)
The present example relates to the structure described in Embodiment 1 with reference to FIG. 3.

10% by mass of manganese acetylacetonate (total mass of metal oxide particles) was added to metal oxide particles containing Mn:Ni:Al in a ratio of 4:1:1 (atomic ratio) and having an average particle size of about 0.2 μm. The mixture was added for 16 hours, and the raw material mixture was prepared using ethanol as a solvent and mixed for 16 hours. The raw material mixture thus obtained in the form of a slurry was supplied in the form of a sheet having a thickness of 10 μm by a doctor blade method onto a copper foil (lower electrode) having a thickness of 30 μm. This sheet was dried at 100° C. for 10 hours and then heated at 150° C. for 30 minutes under a pressure of 100 MPa using a heating press machine. After that, another copper foil (upper electrode) having a thickness of 30 μm is overlaid on the film (metal oxide-containing composite layer) derived from the above sheet, and again using a heat press machine at 250° C. under a pressure of 100 MPa. And heated for 30 minutes to obtain a precursor structure. This precursor structure is annealed at 250° C. for 10 hours to remove unnecessary organic substances that may remain, and thus the structure of this example (a metal oxide-containing composite that can function as a thermistor layer between two copper foils). A structure in which the body layers were sandwiched, and the total thickness was about 70 μm) was obtained.

The bonding strength (adhesiveness) of the structure of this example obtained above was evaluated. This evaluation was performed according to the cross-cut method defined in JIS K5600-5-6. The evaluation results are classified as follows.
0: The edges of the cut are completely smooth, and there is no peeling in any grid.
1: Small peeling of the coating film at the intersection of cuts. The cross-cut portion is clearly not affected by more than 5%.
2: The coating is stripped along the edges of the cut and/or at intersections. The cross-cut portion is clearly affected by more than 5% but never more than 15%.
3: The coating film partially or totally peeled off along the edge of the cut, and/or various portions of the eyes were partially or completely peeled off. The cross-cut portion is clearly affected by more than 15% but not more than 35%.
4: The coating film has a large amount of peeling off partially or entirely along the edge of the cut, and/or some eyes are partially or completely peeled off. The cross-cut portion is clearly not affected by more than 65%.
5: Any of the peeling levels that cannot be classified even in classification 4.

The evaluation result of the bonding strength (adhesiveness) of the structure of this example was Class 1. Specifically, only slight peeling was observed between the upper electrode and the metal oxide-containing composite layer.

Furthermore, the electrical characteristics of the structure of this example were evaluated. More specifically, the structure was cut with a dicing saw to obtain a die having a size of 5 mm×10 mm as viewed from the upper surface and a thickness of 70 μm. With respect to this die, the resistance values at 25° C., 50° C. and 75° C. were measured by the two-terminal method, and the room temperature (25° C.) resistivity and B constant were calculated from the measured values. As a result, the room temperature resistivity was 100 kΩcm and the B constant was 4500.

The evaluation result of the electrical characteristics of the structure of this example shows that the metal oxide particles used in the raw material mixture are heated at 900° C. for 120 minutes at atmospheric pressure and sintered to form a Ag electrode by sputtering on a bulk body. It was substantially in agreement with the electrical characteristics of the prepared sample. Therefore, it was confirmed that the structure of the present example did not substantially increase the resistance at the grain boundaries of the metal oxide particles or at the interface with the electrode.

Furthermore, after the sample of the present example (the above-mentioned die) was left in a constant temperature and high humidity environment of a temperature of 60° C. and a humidity of 95% for 24 hours, the resistance value was measured again, and the resistance at 25° C. measured above was measured. The rate of change based on the value was 0.3%.

Furthermore, FIGS. 13(a) to 13(d) show the results (bright-field image) obtained by enlarging a part of the cross section of the structure of this example and imaging it with a scanning transmission electron microscope (STEM). FIG. 13A is a STEM observation image of a cross section of the junction between the metal oxide-containing composite layer and the lower electrode in the structure of Example 1 and the vicinity thereof. FIG. 13B shows the element distribution of C (carbon) in FIG. FIG. 13C shows the element distribution of Mn (manganese) in FIG. 13A. FIG. 13D shows the element distribution of Cu (copper) in FIG. 13A. As can be understood from FIGS. 13(a) to 13(d), a plurality of particles of metal oxide particles are present in the main body portion of the metal oxide-containing composite layer (a portion excluding the vicinity of the interface between the upper electrode and the lower electrode). It was confirmed that the boundary was in contact with the first amorphous phase and the metal oxide particles were bonded to each other in the first amorphous phase to form a composite. Further, as understood from FIGS. 13(a) to 13(d), at the joint between the metal oxide-containing composite layer and the lower electrode, the composite of the metal oxide particles and the second amorphous phase serves as the bonding layer. It was confirmed that the second amorphous phase formed was a state in which, in addition to Mn, which is a metal element derived from metal oxide particles and metal acetylacetonate, a metal element Cu derived from a metal part was also included.

From the results of the above electrical characteristics and the results of STEM observation, it is presumed that the first amorphous phase and the second amorphous phase have electrical characteristics close to those of the metal oxide (semiconductor) particles. It is considered that the electrical properties equivalent to those of the bulk body sintered at 900° C. were achieved as described above without substantially increasing the resistance at the grain boundaries and at the interface with the electrode.

Further, FIGS. 15(a) to 15(c) show the results obtained by enlarging a part of another cross section of the structure obtained in this example and imaging it with a transmission electron microscope (TEM). With reference to FIGS. 15(a) to (c), no first amorphous phase was observed between the metal oxide particles (first particles) at this portion. The determination as to whether or not the amorphous phase exists was made based on an electron diffraction image, which is a method known to those skilled in the art. When there is no lattice fringe as shown in FIG. 15C, no diffraction spot (dot) is observed as shown in FIG. 15D as an example, which means that an amorphous phase exists. At the measurement points shown in FIGS. 15A to 15C, no amorphous phase having a thickness of 0.01 μm or more was confirmed. From this, it is shown that there may be a place where the first amorphous phase does not exist at all.

(Examples 2 and 3)
The present example relates to the structure described in Embodiment 2 with reference to FIG.

The raw material mixture was prepared by further adding a polyimide precursor solution (Example 2) or a polyamideimide precursor solution (Example 3) at a ratio of 10 mass% (based on the total mass of the metal oxide particles). A structure was obtained in the same manner as in Example 1 except for the above.

The bonding strength (adhesiveness) and electrical characteristics of the structures obtained in the present example obtained above were evaluated in the same manner as in Example 1.

The evaluation results of the bonding strength (adhesiveness) of the structures of these examples were all Class 0. Specifically, no peeling was observed between the upper electrode and the metal oxide-containing composite layer and between the lower electrode and the metal oxide-containing composite layer.

The evaluation results of the electrical characteristics of the structures of these examples were equivalent to those of the structure of Example 1. Furthermore, after the samples of these examples were left in a constant temperature and high humidity environment of a temperature of 60° C. and a humidity of 95% for 24 hours, the resistance values were measured again, and the resistance value at 25° C. measured above was used as a reference. The change rate was 0.1%.

Furthermore, a part of the cross section of the structure of Example 3 was enlarged and imaged with a scanning transmission electron microscope (STEM) (bright field image), and the results are shown in FIGS. 14(a) to (d). 14A to 14D are different from FIGS. 13A to 13D in the distribution of C shown in FIG. 14B. In FIG. 13B, C was observed to be dispersed almost uniformly in the metal oxide-containing composite layer. It is considered that this is because the carbon component accompanying sample processing and measurement was detected. On the other hand, in FIG. 14B, a large amount of C was observed in the region where the metal oxide particles did not exist. From this, it was confirmed that the added polyamideimide precursor liquid was segregated as polyamideimide resin particles.

Therefore, in these Examples 2 and 3, it is understood that the resin particles are formed during the heat treatment under the pressure, and the average particle diameter of the resin particles is larger than the average particle diameter of the metal oxide particles. Understood to be small.

(Example 4)
This example relates to the thermistor described in the first embodiment with reference to FIG.

10% by mass of manganese acetylacetonate (total mass of metal oxide particles) was added to metal oxide particles containing Mn:Ni:Al in a ratio of 4:1:1 (atomic ratio) and having an average particle size of about 0.2 μm. The mixture was added for 16 hours, and the raw material mixture was prepared using ethanol as a solvent and mixed for 16 hours. The raw material mixture thus obtained in the form of a slurry was supplied in the form of a sheet having a thickness of 10 μm on a copper foil having a thickness of 10 μm by the doctor blade method. This sheet was dried at 100° C. for 10 hours and then heated at 250° C. for 30 minutes under a pressure of 100 MPa using a heating press machine to obtain a precursor structure. This precursor structure was annealed at 250° C. for 10 hours to remove unnecessary organic substances that could remain, to obtain a structure. Then, a precursor solution of polyamideimide was applied to a film (metal oxide-containing composite layer capable of functioning as a thermistor layer) derived from the sheet in the obtained structure in a thickness of 10 μm, and the temperature was set to 200° C. At 1 hour, the polyamide-imide was thermally cured to obtain a resin base material. After that, a resist is applied to the surface of the copper foil opposite to the resin base material in a predetermined pattern, exposed and developed, a predetermined portion of the copper foil is removed by etching, and the remaining resist is removed to remove two A copper electrode was formed. Each of these copper electrodes had a dimension of 2.5 mm×2.5 mm when viewed from the top surface and were arranged in parallel at a distance of 100 μm (indicated by a symbol “d” in FIG. 5). After that, the structure was cut with a dicing saw to obtain a thermistor having a size of 5 mm×15 mm as viewed from the upper surface (see FIG. 5).

Regarding the electrical characteristics of the thermistor of this example, the temperature (and its change) was detected from the resistance value (and its change) between two electrodes existing on the same surface of the metal oxide-containing composite layer (thermistor layer). can do. Both the distance d between the electrodes and the thickness t of the metal oxide-containing composite layer contribute to the resistance value of the thermistor. In order to obtain a high temperature resolution, it is considered important to reduce the variation in the resistance value of the thermistor to a certain level or less. The variation in the distance d between the electrodes can be reduced by using, for example, a comb-shaped electrode.

(Example 5)
This example relates to the thermistor described in the first embodiment with reference to FIG.

Mn:Ni:Al at a ratio of 4:1:1 (atomic ratio), with an average particle size of about 0.2 μm, manganese acetylacetonate of 10 mass% (based on the total mass of the metal oxide particles). The mixture was added in a ratio, ethanol was used as a solvent to prepare a raw material mixture, and the mixture was mixed for 16 hours. The raw material mixture thus obtained in the form of a slurry was supplied in the form of a sheet having a thickness of 10 μm on a copper foil having a thickness of 10 μm by the doctor blade method. This sheet was dried at 100° C. for 10 hours and then heated at 150° C. for 30 minutes under a pressure of 100 MPa using a heating press machine to obtain a laminate. The obtained laminated body was cut with a dicing saw to obtain a first laminated body having a size of 5 mm×5 mm as viewed from the upper surface. Separately, a second laminate was prepared in which a copper layer having a thickness of 10 μm was patterned on a polyimide film having a thickness of 20 μm. A film derived from the sheet of the first laminate (a metal oxide-containing composite layer capable of functioning as a thermistor layer) and a copper layer of the second laminate are appropriately opposed to each other with respect to the first laminate and the second laminate. Then, the precursor structure was obtained by heating and heating at 250° C. for 30 minutes under a pressure of 100 MPa using a heating press machine. This precursor structure was annealed at 250° C. for 10 hours to remove unnecessary organic substances that could remain, to obtain a structure. After that, among the obtained structures, a polyimide film having a thickness of 10 μm was covered on the surface of the copper foil of the first laminated body and thermally cured to obtain a multilayer structure. Then, this multilayer structure was cut with a dicing saw to obtain a thermistor having a size of 5 mm×15 mm as viewed from the upper surface (see FIG. 6).

Regarding the electrical characteristics of the thermistor of this example, the resistance value (and its change) between two electrodes facing each other with the metal oxide-containing composite layer (thermistor layer) interposed therebetween (the resistance value is the metal electrode of FIG. 6). The temperature (and its change) can be detected from the resistance value between 13g and 13i and the resistance value between the metal electrodes 13i and 13h. The resistance value of this thermistor is contributed by the area of the opposing region of these electrodes and the thickness t of the metal oxide-containing composite layer. Comparing the thermistor of the present embodiment with the thermistor of the fourth embodiment, the distance between the electrodes of the thermistor of the fourth embodiment contributes to the resistance value of the thermistor, while the thermistor of the present embodiment opposes the electrodes. The difference is that the area of the region contributes. The variation in the distance between the electrodes can be reduced by using, for example, a comb tooth-shaped electrode, but the variation in the area of the opposing region of the electrodes can be reduced more easily in the manufacturing process. Therefore, it can be said that the thermistor of the present embodiment can further reduce variations in resistance value of the thermistor more easily than the fourth embodiment.

(Comparative Example 1)
A thin film thermistor corresponding to the structure described in Patent Document 1 was produced.

A SiO ₂ film was formed on the Si wafer by thermal oxidation, and a Pt electrode layer containing oxygen or nitrogen was formed thereon by sputtering. The electrode layer is etched in a predetermined pattern to form an electrode, and a metal oxide having the same composition as the metal oxide particles used in the raw material mixture in Example 1 is sputtered thereon to form a metal oxide film (thermistor). Layer) to form a thin film thermistor.

The bonding strength (adhesiveness) of the structures of the present comparative example obtained above was evaluated in the same manner as in Example 1 and was classified into Class 3. Specifically, peeling was observed between the electrode and the metal oxide film.

(Comparative example 2)
A thin film thermistor corresponding to the structure described in Patent Document 2 was produced.

A SiO ₂ film was formed on the Si wafer by thermal oxidation, and a Pt/Ti or Cr electrode layer was formed on the SiO ₂ film by sputtering. The electrode layer is etched in a predetermined pattern to form an electrode, and a metal oxide having the same composition as the metal oxide particles used in the raw material mixture in Example 1 is sputtered thereon to form a metal oxide film (thermistor). Layer) to form a thin film thermistor.

The bonding strength (adhesiveness) of the structures of the present comparative example obtained above was evaluated in the same manner as in Example 1 and was classified into Class 3. Specifically, peeling was observed between the electrode and the metal oxide film.

The composite and structure of the present invention can be incorporated into a thermistor, and the thermistor of the present invention can be used in a wide variety of applications such as a temperature sensor. For example, when the thermistor of the present invention is configured to be flexible as a whole, as a flexible temperature sensor, for example, a vehicle-mounted battery in which ignition or deterioration at high temperature is a problem, temperature measurement for temperature management of a smartphone battery, It can be used for applications such as body temperature measurement in the medical and healthcare fields. However, the present embodiment is not limited to such use.

This application claims priority based on Japanese Patent Application No. 2018-248102 filed in Japan on December 28, 2018, the entire contents of which are incorporated herein by reference.

1 First particles (metal oxide particles)
2 First amorphous phase 3 Second particles (resin particles)
10, 11, 11' Composite 12, 12a, 12b Second amorphous phase 13, 13a, 13b Metal part 13c-13n Metal electrode 14a-14d' External electrode 15, 15a- 15n Bonding layer 16, 16a, 16b Bonding layer 20 , 20a to 20f, 21, 22, 23 Structure 27, 27a, 27b Resin base material 30 to 35 Thermistor

Claims (17)

1. A plurality of first particles made of a metal oxide containing at least one first metal element;
   A composite including a first amorphous phase existing between the plurality of first particles and containing the same metal element as the first metal element, wherein the first metal element contains at least one of Mn and Ni. ..
2. The composite according to claim 1, wherein the first metal element further comprises at least one selected from the group consisting of Fe, Al, Co and Cu.
3. The composite according to claim 1 or 2, further comprising a plurality of second particles made of a first resin, wherein the first amorphous phase is present between the plurality of first particles and the plurality of second particles.
4. The composite according to claim 3, wherein the first resin contains at least one selected from the group consisting of polyethylene terephthalate, polyetherimide, polyamideimide, polyimide, polytetrafluoroethylene, epoxy resin and liquid crystal polymer.
5. The composite according to any one of claims 1 to 4, wherein the first amorphous phase has a thickness of 100 µm or less.
6. The composite according to any one of claims 1 to 5, wherein some of the plurality of first particles are in contact with each other.
7. A plurality of first particles made of a metal oxide containing at least one first metal element;
   A plurality of second particles made of a first resin and a first amorphous phase containing the same metal element as the first metal element;
   The first particles are in contact with each other, the second particles are present inside the first particles in contact with each other, and the first amorphous phase is in contact with the first particles in contact with each other. A composite existing between particles and the second particles, wherein the first metal element contains at least one of Mn and Ni.
8. The composite according to claim 7, wherein the first metal element further comprises at least one selected from the group consisting of Fe, Al, Co and Cu.
9. 9. The composite according to claim 7, wherein the first resin contains at least one selected from the group consisting of polyethylene terephthalate, polyetherimide, polyamideimide, polyimide, polytetrafluoroethylene, epoxy resin and liquid crystal polymer. body.
10. The composite according to claim 7, wherein the first amorphous phase has a thickness of 100 μm or less.
11. A metal part containing at least one second metal element,
    The composite according to any one of claims 1 to 10,
    A structure including a bonding layer located between the metal part and the composite, wherein the bonding layer includes a second amorphous phase containing the same metal element as the first metal element and the second metal element. ..
12. 12. The structure of claim 11, wherein the second metal element comprises at least one selected from the group consisting of Mn, Ni, Fe, Al, Zn, Cr, Ti, Co, Cu, Ag, Au and Pt. body.
13. A resin base material made of a second resin,
    The structure according to claim 11 or 12 arranged on the resin substrate, wherein the metal part includes two metal electrodes.
14. The thermistor according to claim 13, wherein the composite and the bonding layer have a total thickness of 100 μm or less.
15. The thermistor according to claim 13 or 14, wherein the second resin contains at least one selected from the group consisting of polyethylene terephthalate, polyetherimide, polyamideimide, polyimide, polytetrafluoroethylene, epoxy resin and liquid crystal polymer. ..
16. The thermistor according to any one of claims 13 to 15, wherein the two metal electrodes have main surfaces facing each other, and the composite is interposed between the main surfaces.
17. The thermistor according to any one of claims 13 to 16, wherein the two metal electrodes are electrically connected to two external electrodes arranged in a staggered manner in plan view.

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